Filters products are mainly classified by spectral band, spectral characteristics, film material, application characteristics, and other methods.
Spectral bands: UV filter, visible filter, infrared filter;
Spectral characteristics: bandpass filter, cut-off filter, spectral filter, neutral density filter, reflection filter;
Membrane material: soft film filter, hard film filter;
Hard film filters do not refer to the hardness of thin films, but more importantly, their laser damage threshold. Therefore, they are widely used in laser systems, while soft film filters are mainly used in biochemical analyzers.
Bandpass type: Light passing through the selected wavelength band is cut off by light outside the passband. Its optical indicators mainly include center wavelength (CWL) and half bandwidth (FWHM). It is divided into narrowband and broadband. For example, narrowband 808 filter NBF-808.
Short wave pass (also known as low wave pass): Light shorter than the selected wavelength passes through and light longer than that wavelength is cut off. For example, infrared cut-off filter, IBG-650.
Long wave pass (also known as high wave pass): Light longer than the selected wavelength passes through, while light shorter than that wavelength cuts off, such as infrared transmission filters, IPG-800.
